Numerical Simulation of Jet Issuing Diagonally Upward into Density-Stratified Fluid in Cylindrical Tank

This study simulates the behavior of a jet issuing into a two-layer density-stratified fluid in a cylindrical tank and the resulting mixing phenomena. The upper and lower fluids are water and an aqueous solution of sodium chloride (NaCl), respectively, with the lower fluid issuing diagonally upward from a nozzle on the bottom of the tank. The angle between the centerline of the jet and the tank bottom is 60°. The phenomena when the Reynolds number Re of the jet is 475, 1426, and 2614 are simulated. The mass concentration of the aqueous solution of NaCl is 0.02. The simulation successfully grasps the jet behavior and the resulting mixing, which agree with the authors’ experimental results at the corresponding Re value. The secondary flows that appear in the horizontal cross-sections consist of a pair of vortices and flows along the tank wall. The secondary flow at the density interface represents the intrusion of an internal density current, which gives rise to mixing along the interface.

Behavior of a Jet Issuing Diagonally Upward into Two-Layer Density-Stratified Fluid in a Cylindrical Tank

This study is concerned with the experimental investigation of a jet issuing diagonally upward into a two-layer density-stratified fluid in a cylindrical tank and the resulting mixing phenomena. The upper and lower fluids are water and an aqueous solution of sodium chloride (NaCl), respectively, and the lower fluid issues from a nozzle on the bottom of the tank. The angle between the centerline of the jet and the bottom of the tank is 60o, and the mass concentration of the NaCl solution is 0.02. The investigation reveals that secondary flow is caused by the jet in the horizontal cross-sections of the tank and that it is composed of a pair of vortices. It confirms that the secondary flow at the density interface corresponds to an internal density current. The investigation also clarifies the effect of the Reynolds number of the jet on mixing between the lower and upper fluids.

Condom-Assisted Transurethral Resection: A New Surgical Technique for Urethral Tumor

Backgrounds: It is difficult to develop clear endoscopic field during transurethral resection (TUR) of urethral tumors, because irrigation water easily spills out from the meatus. We have devised a surgical technique to facilitate TUR of urothelial tumors. Methods: A 79-year old man developed urethral tumors in the anterior urethra and fossa navicularis 6 months after TUR of bladder tumor. We covered his penis and the resectoscope with a tip-cut condom. The tip-end of condom and the resectoscope sheath was tightly sealed and irrigation water was filled inside the condom. Results: The urethral tumors were successfully resected under a clear vision by filling irrigation water inside a tip-cut condom that covered over the resectoscope and the penis. Conclusion: This technique may be useful for TUR of anterior urethral tumors, especially tumors at fossa navicularis, which is often associated with difficulty in obtaining clear surgical vision.

Discovery, invention and serendipity

This paper attempts to relate serendipity, the natural ability to make interesting or valuable discoveries by accident （Longman Discovery of Contemporary English） with notable discoveries and inventions. It connotes the profound ability of finding out valuable things different from those who have been exploring by spending a lot of time or for years. The author will illustrate as many cases as possible within a given time constraint, so that surrounding environments and situations may be clarified, and such discoveries and inventions may be plausibly accomplished by accident or with rich reasons. These illustrations include historical as well as more recent cases. One of the cases is beyond the scope of our environment on the earth with preconceived notion, while other cases have given great impacts to our politics and also military intelligence. It should be noted that business and technological intelligence are deeply connected with discoveries, inventions and serendipity. In concluding remarks, the essence of serendipity will be summarized and how to side with the serendipity at the most important moment will be examined by viewing time series endeavors of the inventors and those who have devoted much time to discoveries.

A prolonged granitoid formation in Saglek Block,Labrador:Zonal growth and crustal reworking of continental crust in the Eoarchean

The Archean continental crusts account for ca.20% of the present volume,but the thermal history of the Earths＇ mantle suggests much more continental crusts were formed in the early Archean.Because the Archean continental crust underwent severe metamorphism,it is important to avoid influence by the later thermal events.We carried out a comprehensive geochronological work of Cathodoluminescence（CL） observation and U-Pb dating of zircons from orthogneisses and supracrustal rocks over the Saglek Block to obtain their protolith ages.The zircons were classified into three domains of core,mantle and rims,and the cores were further classified into three groups of inherited,altered and zoned cores based on the zonation on the CL images.We estimated the protolith ages from Pb-Pb ages of the zoned-cores of zircons with low U contents.We made a detailed sketch of a small outcrop in St.John＇s Harbour South（SJHS） area,and classified the orthogneisses and mafic enclaves into seven generations based on the geologic occurrence.The first and second generations comprise mafic rocks and lack magmatic zircons.We conducted CL imaging and U-Pb dating of zircons from the third,sixth and seventh generation of the orthogneisses to estimate the protolith ages at 3902 L 25,3892 ± 33 and 3897 ± 33 Ma for each,supporting the presence of the over 3.9 Ca Iqaluk Gneiss.The geological occurrence that the mafic rocks occur as enclaves within the 3.9 Ga Iqaluk Gneiss indicates that they are the oldest supracrustal rocks in the world.Our geochronological and geological studies show the Uivak Gneiss is quite varied in lithology and age from 3.6 to 〉3.9 Ga,and tentatively classified into six groups based on their ages.The oldest Uivak Gneiss components including the Iqaluk Gneiss are present around the SJHS area,and the orthogneisses become young as it is away.The lines of evidence of overprinting of younger granitoid on older granitoid in small outcrops and geological-map scale as well as presence of inherited zircons even in the oldest suite suggests that crustal reworking played an important role on erasing the ancient crusts.